Address feedback from ikelos

volatility3/framework/plugins/linux/psaux.py

@@ -4,6 +4,7 @@
 
 from typing import Optional
 
+from volatility3.framework.configuration import requirements
 from volatility3.framework import symbols, exceptions, renderers, interfaces
 from volatility3.framework.objects import utility
 from volatility3.plugins.linux import pslist
@@ -11,6 +12,19 @@ from volatility3.plugins.linux import pslist
 class PsAux(pslist.PsList):
     """ Lists processes with their command line arguments """
 
+    @classmethod
+    def get_requirements(cls):
+        # Since we're calling the plugin, make sure we have the plugin's requirements
+        return [
+            requirements.ModuleRequirement(name = 'kernel', description = 'Linux kernel',
+                                           architectures = ["Intel32", "Intel64"]),
+            requirements.PluginRequirement(name = 'pslist', plugin = pslist.PsList, version = (2, 0, 0)),
+            requirements.ListRequirement(name = 'pid',
+                                         description = 'Filter on specific process IDs',
+                                         element_type = int,
+                                         optional = True)
+        ]
+
     def _get_command_line_args(self, task: interfaces.objects.ObjectInterface,
                                     name: str) -> Optional[str]:
         """
@@ -41,7 +55,7 @@ class PsAux(pslist.PsList):
 
             # get the size of the arguments with sanity checking
             size_to_read = task.mm.arg_end - task.mm.arg_start
-            if size_to_read < 1 or size_to_read > 4096:
+            if not (0 < size_to_read <= 4096):
                 return renderers.UnreadableValue()
 
             # attempt to read it all as partial values are invalid and misleading
@@ -65,13 +79,11 @@ class PsAux(pslist.PsList):
 
         return args
 
-    def _generator(self):
+    def _generator(self, tasks):
         """ Generates a listing of processes along with command line arguments """
 
-        vmlinux = self.context.modules[self.config['kernel']]
-
         # walk the process list and report the arguments
-        for task in self.list_tasks(self.context, vmlinux.name):
+        for task in tasks:
             pid = task.pid
 
             try:
@@ -86,5 +98,11 @@ class PsAux(pslist.PsList):
             yield (0, (pid, ppid, name, args))
 
     def run(self):
-        return renderers.TreeGrid([("PID", int), ("PPID", int), ("COMM", str), ("ARGS", str)], self._generator())
+        filter_func = pslist.PsList.create_pid_filter(self.config.get('pid', None))
+
+        return renderers.TreeGrid([("PID", int), ("PPID", int), ("COMM", str), ("ARGS", str)],
+                                    self._generator(
+                                        pslist.PsList.list_tasks(self.context,
+                                                                self.config['kernel'],
+                                                                filter_func = filter_func)))